1. Field of the Invention
The present invention relates to a surface mount connector to be mounted onto a printed circuit board having conductor pads staggered on its surface.
2. Related Art
A surface mount connector comprises male and female parts, each being so designed as to be mounted onto a printed circuit board whose conductor pads are staggered on its surface for high-density mount. Referring FIG. 5, for example, two lines of conductor pads 13 and 14 are arranged on each side of the midline xe2x80x9ccxe2x80x9d. One of the two lines of conductor pads is closer to the midline xe2x80x9ccxe2x80x9d than the other line; the pads 14 are apart from the midline xe2x80x9ccxe2x80x9d by the short distance xe2x80x9caxe2x80x9d, and are staggered with the pads 13, which are apart from the midline xe2x80x9ccxe2x80x9d by the long distance xe2x80x9cbxe2x80x9d. The long-distant pads 13 arranged on the opposite sides are symmetric with respect to the mid line xe2x80x9ccxe2x80x9d, and likewise, the short-distant pads 14 arranged on the opposite sides are symmetric with respect to the mid line xe2x80x9ccxe2x80x9d. The pads 13 and 14 may be arranged asymmetrically on the opposite sides with respect to the mid line xe2x80x9ccxe2x80x9d.
Referring to FIGS. 6(A) and 6(B), the male part uses two kinds of contact pieces 15a and 15b. The first kind of contact piece 15a has a lead projection formed on its horizontal base, the lead projection being apart from its upright male contact arm. Specifically the lead projection is so placed on the bottom of the horizontal base that it may be apart from the midline xe2x80x9ccxe2x80x9d by the long distances xe2x80x9cbxe2x80x9d, thereby permitting it to confront a selected conductor pad 13 when the male part is mounted on to the printed circuit board 11. Likewise, the second kind of contact piece 15b has a lead projection formed on its horizontal base, the lead projection being close to its upright male contact arm. Specifically the lead projection is so placed on the bottom of the horizontal base that it may be apart from the midline xe2x80x9ccxe2x80x9d by the short distances xe2x80x9caxe2x80x9d, thereby permitting it to confront a selected conductor pad 14 when the male part is mounted on to the printed circuit board 11.
Similarly the female part uses two kinds of contact pieces 16a and 16b as shown in FIGS. 7(A) and 7(B). These different contact pieces are different only in respect of whether their lead projections are close to or remote from their upright contact arms. Such a conventional surface mount connector (stacking connector) is disclosed in JP 5-283131(A), particularly FIG. 1.
The conventional surface mount connector uses two different contact pieces to be mounted in each of the male and female parts. This causes significant disadvantage, which would not be caused if the male or female part used one and same contact piece; first, the number of parts to be assembled increases, and second, two different contact pieces need to be carefully distinguished and inserted alternately into contact slots of the housing. Apparently this is tedious work.
One object of the present invention is to provide a surface mount connector whose male or female part uses one and same kind of contact pieces.
To attain this object a surface mount connector whose male or female part is to be mounted onto a printed circuit board having conductor pads on its surface, these conductor pads being so arranged in two lines on each side of a given midline that the first line of conductor pads is closer to the midline than the second line of conductor pads, and that the conductor pads of the first line are staggered with those of the second line on each side, is improved according to the present invention in that each of the male or female part comprises an insulating housing and a plurality of male or female contact pieces mounted to the insulating housing in two lines, symmetrically relative to the midline of the housing, each male or female contact piece having two lead projections so placed apart from each other that the lead projections may be put in contact with the conductor pads of the first and second lines when the male or female part is mounted onto the printed circuit board.
Each male or female contact piece has two lead projections, and these lead projections are so placed apart from each other on the horizontal base bottom of the contact piece that either one may be put in contact with the conductor pad of the first or second line on the printed circuit board. Male or female contact pieces are punched into one and same shape and size. Also advantageously, use of one and same male or female contact pieces facilitates the mounting of contact pieces to the housing; it is not required that contact pieces are distinguished in respect of their shapes when inserting them into the contact slots of the housing.
Other objects and advantages of the present invention will be understood from the following description of a surface mount connector according to one embodiment of the present invention, which is shown in accompanying drawings.